<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */

/**
 * @see Zend_Db_Adapter_Abstract
 */
require_once 'Zend/Db/Adapter/Abstract.php';

/**
 * @see Zend_Db_Statement_Sqlsrv
 */
require_once 'Zend/Db/Statement/Sqlsrv.php';

/**
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Sqlsrv extends Zend_Db_Adapter_Abstract
{
	/**
	 * User-provided configuration.
	 *
	 * Basic keys are:
	 *
	 * username => (string) Connect to the database as this username.
	 * password => (string) Password associated with the username.
	 * dbname   => The name of the local SQL Server instance
	 *
	 * @var array
	 */
	protected $_config = array(
        'dbname'       => null,
        'username'     => null,
        'password'     => null,
	);

	/**
	 * Last insert id from INSERT query
	 *
	 * @var int
	 */
	protected $_lastInsertId;

	/**
	 * Query used to fetch last insert id
	 *
	 * @var string
	 */
	protected $_lastInsertSQL = 'SELECT SCOPE_IDENTITY() as Current_Identity';

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE,
        'INT'                => Zend_Db::INT_TYPE,
        'SMALLINT'           => Zend_Db::INT_TYPE,
        'TINYINT'            => Zend_Db::INT_TYPE,
        'BIGINT'             => Zend_Db::BIGINT_TYPE,
        'DECIMAL'            => Zend_Db::FLOAT_TYPE,
        'FLOAT'              => Zend_Db::FLOAT_TYPE,
        'MONEY'              => Zend_Db::FLOAT_TYPE,
        'NUMERIC'            => Zend_Db::FLOAT_TYPE,
        'REAL'               => Zend_Db::FLOAT_TYPE,
        'SMALLMONEY'         => Zend_Db::FLOAT_TYPE,
	);

	/**
	 * Default class name for a DB statement.
	 *
	 * @var string
	 */
	protected $_defaultStmtClass = 'Zend_Db_Statement_Sqlsrv';

	/**
	 * Creates a connection resource.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	protected function _connect()
	{
		if (is_resource($this->_connection)) {
			// connection already exists
			return;
		}

		if (!extension_loaded('sqlsrv')) {
			/**
			 * @see Zend_Db_Adapter_Sqlsrv_Exception
			 */
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception('The Sqlsrv extension is required for this adapter but the extension is not loaded');
		}

		$serverName = $this->_config['host'];
		if (isset($this->_config['port'])) {
			$port        = (integer) $this->_config['port'];
			$serverName .= ', ' . $port;
		}

		$connectionInfo = array(
            'Database' => $this->_config['dbname'],
		);

		if (isset($this->_config['username']) && isset($this->_config['password']))
		{
			$connectionInfo += array(
                'UID'      => $this->_config['username'],
                'PWD'      => $this->_config['password'],
			);
		}
		// else - windows authentication

		if (!empty($this->_config['driver_options'])) {
			foreach ($this->_config['driver_options'] as $option => $value) {
				// A value may be a constant.
				if (is_string($value)) {
					$constantValue = @constant(strtoupper($value));
					if ($constantValue === null) {
						$connectionInfo[$option] = $value;
					} else {
						$connectionInfo[$option] = $constantValue;
					}
				}
			}
		}

		$this->_connection = sqlsrv_connect($serverName, $connectionInfo);

		if (!$this->_connection) {
			/**
			 * @see Zend_Db_Adapter_Sqlsrv_Exception
			 */
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception(sqlsrv_errors());
		}
	}

	/**
	 * Check for config options that are mandatory.
	 * Throw exceptions if any are missing.
	 *
	 * @param array $config
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _checkRequiredOptions(array $config)
	{
		// we need at least a dbname
		if (! array_key_exists('dbname', $config)) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'dbname' that names the database instance");
		}

		if (! array_key_exists('password', $config) && array_key_exists('username', $config)) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'password' for login credentials.
                                                If Windows Authentication is desired, both keys 'username' and 'password' should be ommited from config.");
		}

		if (array_key_exists('password', $config) && !array_key_exists('username', $config)) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'username' for login credentials.
                                                If Windows Authentication is desired, both keys 'username' and 'password' should be ommited from config.");
		}
	}

	/**
	 * Set the transaction isoltion level.
	 *
	 * @param integer|null $level A fetch mode from SQLSRV_TXN_*.
	 * @return true
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	public function setTransactionIsolationLevel($level = null)
	{
		$this->_connect();
		$sql = null;

		// Default transaction level in sql server
		if ($level === null)
		{
			$level = SQLSRV_TXN_READ_COMMITTED;
		}

		switch ($level) {
			case SQLSRV_TXN_READ_UNCOMMITTED:
				$sql = "READ UNCOMMITTED";
				break;
			case SQLSRV_TXN_READ_COMMITTED:
				$sql = "READ COMMITTED";
				break;
			case SQLSRV_TXN_REPEATABLE_READ:
				$sql = "REPEATABLE READ";
				break;
			case SQLSRV_TXN_SNAPSHOT:
				$sql = "SNAPSHOT";
				break;
			case SQLSRV_TXN_SERIALIZABLE:
				$sql = "SERIALIZABLE";
				break;
			default:
				require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
				throw new Zend_Db_Adapter_Sqlsrv_Exception("Invalid transaction isolation level mode '$level' specified");
		}

		if (!sqlsrv_query($this->_connection, "SET TRANSACTION ISOLATION LEVEL $sql;")) {
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception("Transaction cannot be changed to '$level'");
		}

		return true;
	}

	/**
	 * Test if a connection is active
	 *
	 * @return boolean
	 */
	public function isConnected()
	{
		return (is_resource($this->_connection)
		&& (get_resource_type($this->_connection) == 'SQL Server Connection')
		);
	}

	/**
	 * Force the connection to close.
	 *
	 * @return void
	 */
	public function closeConnection()
	{
		if ($this->isConnected()) {
			sqlsrv_close($this->_connection);
		}
		$this->_connection = null;
	}

	/**
	 * Returns an SQL statement for preparation.
	 *
	 * @param string $sql The SQL statement with placeholders.
	 * @return Zend_Db_Statement_Sqlsrv
	 */
	public function prepare($sql)
	{
		$this->_connect();
		$stmtClass = $this->_defaultStmtClass;

		if (!class_exists($stmtClass)) {
			/**
			 * @see Zend_Loader
			 */
			require_once 'Zend/Loader.php';
			Zend_Loader::loadClass($stmtClass);
		}

		$stmt = new $stmtClass($this, $sql);
		$stmt->setFetchMode($this->_fetchMode);
		return $stmt;
	}

	/**
	 * Quote a raw string.
	 *
	 * @param string $value     Raw string
	 * @return string           Quoted string
	 */
	protected function _quote($value)
	{
		if (is_int($value)) {
			return $value;
		} elseif (is_float($value)) {
			return sprintf('%F', $value);
		}

		return "'" . str_replace("'", "''", $value) . "'";
	}

	/**
	 * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
	 *
	 * As a convention, on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
	 * from the arguments and returns the last id generated by that sequence.
	 * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
	 * returns the last value generated for such a column, and the table name
	 * argument is disregarded.
	 *
	 * @param string $tableName   OPTIONAL Name of table.
	 * @param string $primaryKey  OPTIONAL Name of primary key column.
	 * @return string
	 */
	public function lastInsertId($tableName = null, $primaryKey = null)
	{
		if ($tableName) {
			$tableName = $this->quote($tableName);
			$sql       = 'SELECT IDENT_CURRENT (' . $tableName . ') as Current_Identity';
			return (string) $this->fetchOne($sql);
		}

		if ($this->_lastInsertId > 0) {
			return (string) $this->_lastInsertId;
		}

		$sql = $this->_lastInsertSQL;
		return (string) $this->fetchOne($sql);
	}

	/**
	 * Inserts a table row with specified data.
	 *
	 * @param mixed $table The table to insert data into.
	 * @param array $bind Column-value pairs.
	 * @return int The number of affected rows.
	 */
	public function insert($table, array $bind)
	{
		// extract and quote col names from the array keys
		$cols = array();
		$vals = array();
		foreach ($bind as $col => $val) {
			$cols[] = $this->quoteIdentifier($col, true);
			if ($val instanceof Zend_Db_Expr) {
				$vals[] = $val->__toString();
				unset($bind[$col]);
			} else {
				$vals[] = '?';
			}
		}

		// build the statement
		$sql = "INSERT INTO "
		. $this->quoteIdentifier($table, true)
		. ' (' . implode(', ', $cols) . ') '
		. 'VALUES (' . implode(', ', $vals) . ')'
		. ' ' . $this->_lastInsertSQL;

		// execute the statement and return the number of affected rows
		$stmt   = $this->query($sql, array_values($bind));
		$result = $stmt->rowCount();

		$stmt->nextRowset();

		$this->_lastInsertId = $stmt->fetchColumn();

		return $result;
	}

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables()
	{
		$this->_connect();
		$sql = "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";
		return $this->fetchCol($sql);
	}

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @todo Discover integer unsigned property.
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null)
	{
		/**
		 * Discover metadata information about this table.
		 */
		$sql    = "exec sp_columns @table_name = " . $this->quoteIdentifier($tableName, true);
		$stmt   = $this->query($sql);
		$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);

		$owner           = 1;
		$table_name      = 2;
		$column_name     = 3;
		$type_name       = 5;
		$precision       = 6;
		$length          = 7;
		$scale           = 8;
		$nullable        = 10;
		$column_def      = 12;
		$column_position = 16;

		/**
		 * Discover primary key column(s) for this table.
		 */
		$tableOwner = $result[0][$owner];
		$sql        = "exec sp_pkeys @table_owner = " . $tableOwner
		. ", @table_name = " . $this->quoteIdentifier($tableName, true);
		$stmt       = $this->query($sql);

		$primaryKeysResult = $stmt->fetchAll(Zend_Db::FETCH_NUM);
		$primaryKeyColumn  = array();

		// Per http://msdn.microsoft.com/en-us/library/ms189813.aspx,
		// results from sp_keys stored procedure are:
		// 0=TABLE_QUALIFIER 1=TABLE_OWNER 2=TABLE_NAME 3=COLUMN_NAME 4=KEY_SEQ 5=PK_NAME

		$pkey_column_name = 3;
		$pkey_key_seq     = 4;
		foreach ($primaryKeysResult as $pkeysRow) {
			$primaryKeyColumn[$pkeysRow[$pkey_column_name]] = $pkeysRow[$pkey_key_seq];
		}

		$desc = array();
		$p    = 1;
		foreach ($result as $key => $row) {
			$identity = false;
			$words    = explode(' ', $row[$type_name], 2);
			if (isset($words[0])) {
				$type = $words[0];
				if (isset($words[1])) {
					$identity = (bool) preg_match('/identity/', $words[1]);
				}
			}

			$isPrimary = array_key_exists($row[$column_name], $primaryKeyColumn);
			if ($isPrimary) {
				$primaryPosition = $primaryKeyColumn[$row[$column_name]];
			} else {
				$primaryPosition = null;
			}

			$desc[$this->foldCase($row[$column_name])] = array(
                'SCHEMA_NAME'      => null, // @todo
                'TABLE_NAME'       => $this->foldCase($row[$table_name]),
                'COLUMN_NAME'      => $this->foldCase($row[$column_name]),
                'COLUMN_POSITION'  => (int) $row[$column_position],
                'DATA_TYPE'        => $type,
                'DEFAULT'          => $row[$column_def],
                'NULLABLE'         => (bool) $row[$nullable],
                'LENGTH'           => $row[$length],
                'SCALE'            => $row[$scale],
                'PRECISION'        => $row[$precision],
                'UNSIGNED'         => null, // @todo
                'PRIMARY'          => $isPrimary,
                'PRIMARY_POSITION' => $primaryPosition,
                'IDENTITY'         => $identity,
			);
		}

		return $desc;
	}

	/**
	 * Leave autocommit mode and begin a transaction.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	protected function _beginTransaction()
	{
		if (!sqlsrv_begin_transaction($this->_connection)) {
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception(sqlsrv_errors());
		}
	}

	/**
	 * Commit a transaction and return to autocommit mode.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	protected function _commit()
	{
		if (!sqlsrv_commit($this->_connection)) {
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception(sqlsrv_errors());
		}
	}

	/**
	 * Roll back a transaction and return to autocommit mode.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	protected function _rollBack()
	{
		if (!sqlsrv_rollback($this->_connection)) {
			require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
			throw new Zend_Db_Adapter_Sqlsrv_Exception(sqlsrv_errors());
		}
	}

	/**
	 * Set the fetch mode.
	 *
	 * @todo Support FETCH_CLASS and FETCH_INTO.
	 *
	 * @param integer $mode A fetch mode.
	 * @return void
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	public function setFetchMode($mode)
	{
		switch ($mode) {
			case Zend_Db::FETCH_NUM:   // seq array
			case Zend_Db::FETCH_ASSOC: // assoc array
			case Zend_Db::FETCH_BOTH:  // seq+assoc array
			case Zend_Db::FETCH_OBJ:   // object
				$this->_fetchMode = $mode;
				break;
			case Zend_Db::FETCH_BOUND: // bound to PHP variable
				require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
				throw new Zend_Db_Adapter_Sqlsrv_Exception('FETCH_BOUND is not supported yet');
				break;
			default:
				require_once 'Zend/Db/Adapter/Sqlsrv/Exception.php';
				throw new Zend_Db_Adapter_Sqlsrv_Exception("Invalid fetch mode '$mode' specified");
				break;
		}
	}

	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param string $sql
	 * @param integer $count
	 * @param integer $offset OPTIONAL
	 * @return string
	 * @throws Zend_Db_Adapter_Sqlsrv_Exception
	 */
	public function limit($sql, $count, $offset = 0)
	{
		$count = intval($count);
		if ($count <= 0) {
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
		}

		$offset = intval($offset);
		if ($offset < 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
		}

		$orderby = stristr($sql, 'ORDER BY');
		if ($orderby !== false) {
			$sort  = (stripos($orderby, ' desc') !== false) ? 'desc' : 'asc';
			$order = str_ireplace('ORDER BY', '', $orderby);
			$order = trim(preg_replace('/\bASC\b|\bDESC\b/i', '', $order));
		}

		$sql = preg_replace('/^SELECT\s/i', 'SELECT TOP ' . ($count+$offset) . ' ', $sql);

		$sql = 'SELECT * FROM (SELECT TOP ' . $count . ' * FROM (' . $sql . ') AS inner_tbl';
		if ($orderby !== false) {
			$sql .= ' ORDER BY ' . $order . ' ';
			$sql .= (stripos($sort, 'asc') !== false) ? 'DESC' : 'ASC';
		}
		$sql .= ') AS outer_tbl';
		if ($orderby !== false) {
			$sql .= ' ORDER BY ' . $order . ' ' . $sort;
		}

		return $sql;
	}

	/**
	 * Check if the adapter supports real SQL parameters.
	 *
	 * @param string $type 'positional' or 'named'
	 * @return bool
	 */
	public function supportsParameters($type)
	{
		if ($type == 'positional') {
			return true;
		}

		// if its 'named' or anything else
		return false;
	}

	/**
	 * Retrieve server version in PHP style
	 *
	 * @return string
	 */
	public function getServerVersion()
	{
		$this->_connect();
		$version = sqlsrv_client_info($this->_connection);

		if ($version !== false) {
			return $version['DriverVer'];
		}

		return null;
	}
}
